Define an acid and a base. Give two examples of each. (b) Give the names and formulae of two strong bases and two weak bases. (c) What type of ions are formed: (i) when an acid is dissolved in water? (ii) when a base (or alkali) is dissolved in water? (d) Write the neutralisation reaction between acids and bases in terms of the ions involved. Write any two important uses of bases

• Acids are those substance when dissolved in water dissociates completely to produce hydrogen ions and tastes sour. It turns litmus paper from blue to red eg: HCl and H2SO4

Bases are those substance when dissolved in water partially dissociates to produce hydroxide ions and tastes bitter. It changes litmus paper from red to blue eg: NaOH and Mg(OH)2

• Strong bases are Sodium hydroxide NaOH and potassium hydroxide KOH Weak bases are calcium hydroxide Ca(OH)2 and Ammonium hydroxide NH4OH
• (i) Hydrogen ions are formed when an acid dissolves in water

(ii) Hydroxide ions are formed when base dissolved in water

• H+(aq) + OH-(aq) → H2O(l)
• Bases like sodium hydroxide is used to manufacture soap, paper etc and calcium hydroxides are used to manufacture bleaching powder